4、ifficult__________(read).18.I__________(go)tobedwhensomebodyknockedatmydoor.19.Thisdecisionishighly__________(advantage)tous.20.After__________(put)downthebookand__________(pick)upapieceofchalk,ourteacherbeganspeaking.21.Jim'sbirthdayisonthe _____ ofMay(one)22.Mymotherlikes ____. she ____ m